Preparation and application background and overview of 2-amino-3-trifluoromethylpyridine
2-Amino-3-trifluoromethylpyridine is an organic intermediate. 2-fluoro-3-trifluoromethylpyridine can be prepared from 2-chloro-3-trifluoromethylpyridine first, and then Nucleophilic substitution with ammonia gives 2-amino-3-trifluoromethylpyridine. 2-Chloro-3-trifluoromethylpyridine can be used to prepare the intermediate 2-hydroxy-3-trifluoromethylpyridine. 2-Hydroxy-3-trifluoromethylpyridine is a valuable chemical in the fluorine-containing pyridine heterocycles. It is mainly used in pharmaceutical intermediates, organic synthesis, and organic solvents. It can also be used in dye production, pesticide production and Spices, etc.
Preparation and application of 2-amino-3-trifluoromethylpyridine
Preparation and application of 2-amino-3-trifluoromethylpyridine (1) Fluorination
Put 2500g of 2-chloro-3-trifluoromethylpyridine into a 5000ml high-pressure reaction kettle at one time, then add 750g of hydrogen fluoride into the high-pressure reaction kettle, start stirring, and heat up the reaction. The temperature is 210°C and the pressure is not stable. Over 30 bar, react for 48 hours. After the reaction, wash the material with water, neutralize it with sodium hydroxide to a pH value of 7, and then distill it to obtain 2-fluoro-3-trifluoromethylpyridine, with a content of >99% .
Preparation and application of 2-amino-3-trifluoromethylpyridine (2) Amination
Add 750g of 2-fluoro-3-trifluoromethylpyridine into the ammoniation kettle, add 700g of basic bismuth carbonate water to the ammoniation kettle, and then pass 250g of liquid ammonia into the ammoniation kettle and raise the temperature to 180°C , the pressure is not more than 3.0MPa, react for 10 hours, cool to 90°C, discharge into the receiving kettle, cool to 10°C after receiving, centrifuge and dry to obtain 2-amino-3-trifluoromethylpyridine; yield About 95%
Preparation and application of 2-amino-3-trifluoromethylpyridine
Preparation and application of 2-amino-3-trifluoromethylpyridine Application 1.
2-Chloro-3-trifluoromethylpyridine can be used to prepare the intermediate 2-hydroxy-3-trifluoromethylpyridine as follows:
Put 700g of 30% hydrochloric acid into the 2000ml reactor at one time, start stirring, open the cold liquid valve to cool down, and then slowly add 160g of 99% 2-amino-3-trifluoromethylpyridine into the reactor. Inside. Add 143g of 30% sodium nitrite aqueous solution into the metering tank above the reactor. When the temperature in the reactor drops to 10°C, add a certain amount of sodium nitrite aqueous solution dropwise. Control the temperature of the reactor to 10°C during the dripping process. After completion, keep it warm for 2 hours and take samples.
After the reaction is completed and the sampling is qualified, liquid alkali is added to the reaction solution to neutralize the pH value to 7, and the neutralization temperature is controlled at 60°C. After neutralization, the product 2-hydroxy-3-methylpyridine is separated through suction filtration and drying, with a content of >99%.
Preparation and application of 2-amino-3-trifluoromethylpyridine Application 2.
CN200610038262.2 reports the preparation method of the key intermediate 3-trifluoromethyl-2-pyridine sulfonamide of the sulfonylurea herbicide picosulfuron; the method is carried out in three steps: diazotization, alkali Formula bismuth carbonate sulfonyl chlorination reaction and amination reaction. First, 2-amino-3-trifluoromethylpyridine reacts with sodium nitrite under acidic conditions to prepare a diazonium salt, and then reacts with sodium bisulfite under the catalysis of copper chloride to form 3-trifluoromethyl-2-pyridine sulfonate. Acid chloride; finally reacts with ammonia to form 3-trifluoromethyl-2-pyridine sulfonamide. This method is one of the most ideal new methods today for preparing 3-trifluoromethyl-2-pyridine sulfonamide from cheap and easily available raw materials under mild, simple and safe conditions.
References
[1][Chinese invention] Preparation method of CN201711285492.32-hydroxy-3-trifluoromethylpyridine
[2] Preparation method of CN200610038262.23-trifluoromethyl-2-pyridinesulfonamide
